fix: web API 502 — use Podman-local DNS for gateway proxy

Mount nginx template with NGINX_LOCAL_RESOLVERS and require web→gateway health in deploy checks.

Co-authored-by: Cursor <cursoragent@cursor.com>

docs/README.md

@@ -23,7 +23,7 @@
 
 | 改什么 | 文件 | 命令 |
 |--------|------|------|
-| 容器反代 | `web/nginx.conf` | `./reload-config.sh web` |
+| 容器反代 | `web/nginx.conf.template`（compose） | `./reload-config.sh web` |
 | 公开 URL / 发布回执 | `.env` 的 `AIJZ_PUBLIC_BASE_URL` + `platform/etc/platform.docker.yaml` | `./reload-config.sh platform` |
 | Gateway | `gateway/etc/gateway.docker.yaml` | `./reload-config.sh gateway` |
 | LLM Key | `.env` | `./reload-config.sh ai` |